The present invention relates to a method of deactivating catalyst residues in amorphous polyalphaolefins such as amorphous propylene homopolymers and copolymers. More particularly it relates to a novel deactivation method incorporated in bulk polymerization process for the direct production of substantially amorphous polyalphaolefins using a high-activity supported titanium chloride catalyst and an alkylaluminum co-catalyst. The amorphous polymer is the only product of the process and after separation of unreacted monomer(s) and deactivation of catalyst residues present in the polymer, it is conducted to storage at sufficiently elevated temperature to prevent unwanted solidification of the polymer in the process equipment. Often, the equipment for product storage and for transportation of the product to the user are also heated to facilitate withdrawal of the amorphous polymer in the molten stage. In order to prevent degradation due to heat, the polymer must be stabilized with a hindered phenolic antioxidant in accordance with conventional practice.
It was unexpectedly found, however, that when using deactivation and stabilization techniques otherwise conventionally and successfully employed in the production of high molecular weight highly crystalline alphaolefin polymers such as isotactic propylene polymers, the resulting amorphous product was highly unstable. Specifically, when deactivating the catalyst resides by the injection of C.sub.3 -C.sub.8 alcohol such as isopropyl alcohol into the hot devaporized product stream and subsequently adding a commercial hindered phenolic antioxidant, no significant quantities of the hindered phenolic antioxidant could be found by analysis of the supposedly stabilized product.
Also, the deactivation of the chloride containing catalyst residues in the polymer with the alcohol causes the liberation of hydrogen chloride with attendant corrosion problems in conduits and process vessels. A solution to the problem is to add a neutralizer such as aluminum magnesium hydroxycarbonate to the polymer, however, this adds considerably to the cost of the final product.